73M223
1200 Baud FSK Modem
February 1998
DESCRIPTION
The 73M223 modem device receives and transmits
serial and binary data over existing telephone
networks using Frequency Shift Keying (FSK). It
provides the filtering, modulation, and demodulation
to implement a serial, asynchronous data
communication channel. The 73M223 employs the
CCITT V.23 signaling freque ncies of 1302 and 2097
Hz, operating at 1200 baud, and is intended for half
duplex operation over a two-line system.
The 73M223 provides a cost-effective alternative to
existin g modem soluti ons. It is i deally suited for R.F.
data links, credit verification systems, point-of-sale
terminals, and remote process control.
CMOS technology ensures small size, low-power
consumption and enhanced reliability.
FEATURES
•
Low cost FSK Modem
•
1200 baud operation
•
CMOS switched capacitor technology
•
Built-in self-test feature
•
On-chip filtering, and
Modulation/Demodulation
•
Uses CCITT V.23 frequencies
•
On chip crystal oscillator
•
Low power/High reliability
•
Does not require a microprocessor
•
10 mW @ 5 V supply
•
16-pin plastic packages
BLOCK DIAGRAM
OSC1 OSC2
OSC
13 14
TXD
12
TEST
7
16
15
PHASE
COHERENT
WAVE
SYNTHESIZER
PROGRAMMABLE
DIGITAL
DIVIDER
DIGITAL
TIMING
SIGNALS
SYNC
PHASE LOCKED
LOOP
TXA
CLK
9
15
SYNC
TEST
SLICER
RXA
FIL 5
2
DIGITAL
DEMODULATOR
DIGITAL
LP
FILTER
DELAY
TEST
11
RXD
TEST6
RANDOM
SEQUENCE
GENERATOR
SWITCHED CAP
BANDPASS
FILTER
4
RXF
3 CAP 1
VDD
8
VSS
